The present invention relates to methods for protective treatment of coal to maintain quality of the coal during shipment by, inter alia, reducing increase in moisture and volatility of the coal during shipment or storage.
After coal is mined or otherwise recovered, it is generally stored and commences to deteriorate generally by loss of heat value and increase in moisture and volatility. The international market for coal has grown rapidly during recent years and, because most of the coal in the United States is mined in the interior States of the country, it is necessary to ship the coal long distances to ports for overseas transshipment. Typically, the coal is shipped in open railroad cars or barges and during such shipment the moisture content of the coal increases and the heating value, in many instances increases in volatility.
The increased volatility, increased moisture, and decreased heat value which occurs during shipment of coal generally leads to penalties assessed against seller so that upon arrival at a port or other shipping point the coal is reanalyzed and the sale price adjusted accordingly. One reason for the penalty is that in the case of increased moisture the shipper is in effect paying for the overseas shipment of water. In some cases the moisture increase may be significant for example, up to 4% to 6% of the total weight of the coal may be moisture. In such cases, the penalty which must be paid by the seller as reduced selling price may be significant.
In general, the same deterioration occurs in open air storage of coal. Further, even though the coal is generally washed prior to shipment, the shipped coal still includes significant quantities of fines or coal dust which provide a hazard due to the potential of fire since the dust is far more easily ignited than are the coal particles themselves.
No prior art procedure or composition is known for treating coal prior to overland or waterway shipment for a long distance which diminishes the likelihood of accidential ignition and associated hazards due to the burning of the coal dust associated with coal and which substantially reduces the deterioration which occurs during storage or shipment in the open.